The PDF file format was originally created by Adobe in the early ’90s and it now the most popular format for exchanging all sorts of documents including presentations, CAD Drawings, invoices, government forms and other legal documents.
There are several reasons why PDF file format is so popular. PDFs are generally more compact (smaller in size) than the source document and they preserve the original formatting. The content of a PDF file cannot be modified easily and you can prevent other users from printing or copying text from PDF documents. Also, you can open a PDF file on any computer or mobile device natively.

Free PDF Editing Tools

While PDF Files are “read only” by default, there are workarounds that will let you modify any PDF document for free without requiring the source files or any of the commercial PDF editing tools like Adobe Acrobat.
We are primarily focusing on tools that let you alter the actual contents of a PDF files. If you are looking to manipulate the PDF file structure itself like rearranging pages or merging multiple PDFs into one, please refer to this detailed Adobe PDF Guide.

An Online PDF Editor for Basic Tasks

Sometimes you need to make minor changes to a PDF file. For instance, you may want to hide your personal phone number from a PDF file before uploading it online or may want to annotate a page with notes and freehand drawings.
You can perform such edits in a PDF easily with PDFEscape.com, an online PDF editor that is free and also lets you edit password-protected PDF documents in the browser.
With PDF Escape, you can hide* parts of a PDF file using the whiteout tool or add annotations with the help of custom shapes, arrows, text boxes and sticky notes. You can add hyperlinks to other PDF pages / web documents.
[*] Hiding is different from redaction because here we aren’t changing the associated metadata of a PDF file but just hiding certain visible parts of a PDF file by pasting an opaque rectangle over that region so that the stuff beneath the rectangle stays invisible.

Change Metadata of PDF Files

If you would like to edit the meta-data associated* with a PDF document, check out Becy PDFMetaEdit. This is a free utility that can help you edit properties of a PDF document including the title, author name, creation data, keywords, etc.
The tool can also be used for removing PDF passwords as well as for encrypting PDF documents such that only users who know the password can read the contents of your PDF files. And since this PDF metadata plus bookmarks editor can be executed from the command line, you can use it to update information in multiple PDF files in a batch.
[*] If you planning to post your PDF files on the web, you should consider adding proper metadata to all the files as that will help improve the organic rankings of your PDF files in Google search results.

Edit the Text of a PDF File

If you want to edit the text in a PDF file but don’t have access to the source documents, your best bet is that you convert the PDF file into an editable Word document or an Excel spreadsheet depending on the contents of the PDF.
Then edit these converted PDFs in Microsoft Office (or Google Docs) and export the modified files back into PDF format using any PDF writer.
You can edit PDFs in Word or, if your PDF document is mostly text, you may use the desktop version of Stanza to convert that PDF into a Word document. If the document includes images, charts, tables and other complex formatting, try the online PDF to Word converter from BCL Research or the one from NitroPDF – the former offers instant conversion while the latter service can take up to a day though its yields more accurate results.

Advanced PDF Editing (Images, text, etc.)

Now that you know the basic PDF editing tools, let’s look at another set of PDF editors that are also free but can help you do some more advanced editing like replacing images on a PDF file, adding signatures, removing blocks of text without breaking the flow of the document, etc.
First there’s PDF XChange, a free PDF viewer and editor that you also may use for typing text directly on any PDF page. PDF XChange also supports image stamps so you may use the tool for signing PDF files or for inserting images anywhere on a PDF page.
Then you have Inkscape, a free vector drawing tool (like Adobe Illustrator) that can natively import and export PDF content.

Video: How to Edit PDF Files with Inkscape

With Inkscape, you can select any object on a PDF page (including text, graphics, tables, etc.) and move them to a different location or even remove them permanently from the PDF file. You can also annotate PDF files with Inkscape or draw freehand on a page using the built-in pencil tool.
The next tool in the category of advanced PDF editors is OpenOffice Draw with the PDFImport extension. OpenOffice Draw supports inline editing so you can easily fix typos in a PDF document or make formatting related changes like replacing color, increasing or decreasing the text size, replacing the default font-family, etc.
Like Inkscape, the OpenOffice toolbox also includes support for annotations, shapes, images, tables, charts, etc. but here you have more choices and the software also looks less complex.
The OpenOffice suite is a little bulky (they don’t provide a standalone installer for Draw) but if you have the bandwidth, OpenOffice is the best tool for manipulating PDF documents when you don’t have the budget for Adobe Acrobat.

 

 

Sweeter is an open-source facebook-like service (or Facebook clone, which might better describe the service). It’s microblogging combined with Pligg style voting. So you can write whatever you want—about that pie you ate, or about a new site you found—however, if the crowd doesn’t like your posts, you can lose karma points.

9. Laconica facebook clone | Demo | Download

Twitter Clone is an advanced Social Media Script combining social networking and micro-blogging services allowing members to send and receive messages, and tweets, in their native language. It allows the creation of Tweets that are text-based and supported up to 140 characters. Tweets “tweeted” can only be sent to the tweeps, i.e., followers, except for open access tweets. It allows sharing of posts, links, and images directly without third-party services. Twitter Clone Open Source has all the necessary functions and features required for a successful microblogging website. The users today are very much active over such blogging websites that give them an innovative platform for microblogging using hashtagging and connecting people online. It highlights the updates in the "stream" and ‘followers’ will be able to see what’s trending.
Businesses today have occupied Social Media platforms for growing their business and targeting their audience through social platforms. The substantial impulsion toward both social media and branding has made it almost impossible to avoid this social planetary. This enhances their business to lead to more sales and generate huge money. Looking forward to the increasing trend, Twitter PHP Clone can become a helpful tool to start your own social media website and provide resourceful tools to the client.

Salient features of a Twitter Clone Script

• Twitter clone script allows members to manage their profiles. Active members can edit the background image/color of the profile, password, and view/edit/her friends and their tweets.
• Allows users to upload text-based posts, pictures, active links, auto-link users using @username to share their views and ideas
• Enables individuals to unfollow anyone whenever they want to
• Allows members to view the recent updates of their friends to whom they follow
• Twitter clone script enables users to invite friends to join the site
• Multi-Language Support
• Instant Messaging support: MSN, GTalk, AIM, Yahoo Messenger

Sweeter is an opensource Twitter-like service (or Twitter clone, might better describe the service). It’s microblogging combined with Pligg style voting. So you can write whatever you want about that pie you ate, or about a new site you found, however, if the crowd doesn’t like your posts, you can lose karma points.

9. Laconica twitter clone | Demo | Download