Many Blogging applications are free, these are provided under free-software and open-source licenses, allowing them to used, modified, and redistributed freely.
As my opinion, WordPress(user hosted) is the widely used best blogging software and blogger(blogger.com) is widely used best developer-hosted blogging software.
Here is the list of blogging tools that are offered as free and open source software. PHP based software are most famous in blogging.
PHP based
- b2evolution
- Drupal
- FlatPress
- Frog CMS
- Elgg
- Habari
- Jaws
- Joomla
- LifeType
- Nucleus CMS
- Open Blog
- Serendipity
- Textpattern
- WordPress
Java-based
- Apache Roller
Classic ASP
- Battle Blog
VB.NET/ASP.NET
- DotNetNuke
C#/ASP.NET
- Subtext
Perl Based
- Blosxom
- Livejournal
- Movable Type
- Slash
Ruby on Rails
- Typo
[Reference – Wiki]
