I’ve been tracking this release for the last two weeks and then the moment it was announced… my internet connection went down.
Except the case you are already a Cassandra user, the release notes  and the changelog  will probably not make a lot of sense to you. While I have counted around 60 bug fixes and improvements in the changelog, I couldn’t differentiate small bugfixes from really exciting new features/performance improvements.
[…] 0.5 adds proactive repair, what Dynamo calls “anti-entropy,” to synchronize any updates Hinted Handoff or read repair didn’t catch across all replicas for a given piece of data.
0.5 also adds load balancing and significantly improves bootstrap (adding nodes to a running cluster)
in 0.5 we’ve improved concurrency across the board, improving insert speed by over 50% on the stress.py benchmark (from contrib/) on a relatively modest 4-core system with 2GB of ram. We’ve also added a [row] key cache, enabling similar relative improvements in reads
0.5 also brings new tools, including JSON-based data export and import, an improved command-line interface, and new JMX metrics
So, as I expected there are quite a few interesting new things in the new Cassandra 0.5.0.
Still related to Cassandra, it looks like the guys from Twitter will finally talk about their Cassandra usage at the ☞ Official Twitter Developer Conf. Now, I hope that someone from Twitter is reading this and will give MyNoSQL a chance to discuss the details of the Cassandra usage at Twitter and publish an article for all our readers here (note in case you know someone at Twitter please do forward it to them).