Just to sum up, elgg is a social network framework, which gives you the frame to create your own social network, elgg’s social engine powers all kinds of social environments, from education to business and anything inbetween. If you are looking for a professional social intranet or want to run a site for your organisation, Elgg is a great choice.
So far :
We’ve had many issues with elgg, but that’s only because we jumped on board right when 1.0 was released, in Dec 2008, since then elgg has gone through a few different version and is now on 1.6.1, this is as of last week (date of writing Sept14th 2009). Most things in 1.6.1 are now fixed, although some of the extra functionality that we had from the use of plugins from the elgg community have gone, as the core of elgg has been upgraded leaving some of the community plugins no longer working, this has noticeable happened in the Groups plugin, where you now cant edit the a discussion post once it has been created, nor can you change its status from open to closed.
Hopefully the community plugins will be updated in due time.