How to manage the web presence of a research group

There are many things that could be useful for the web presence of a research group, namely:

• A brief presentation of the aims of this research group
• The members of this working group (past and currents) with a link to their homepage
• a list of publications by this research group
• if there are working groups organized by this research group (for instance a presentation every two weeks by one of the member of the work done)
• Other results such as software ...
• Maybe a link to the people funding this research group, a little advertisement never hurts.

To add to Gopi's answer,

• A list of lab alumni and optionally where they currently are working, it can help lend credibility to the lab ("look at how awesome we are, former postdocs from our lab are now working at MIT")

• In the publications section, I would add downloadable PDFs of your papers, as that's the most common reason people will be visiting your website

Regarding your mention of content for the lab specifically (i.e., an intranet), we had such a page in our lab, and we used it solely to distribute (and keep historical records of) papers discussed in lab meetings.

In addition to the components listed by eykanal and Gopi, my group webpage includes pages for

• Software developed by the group
• Open positions (Ph.D. studentships and post-docs) available within the group.

These things could be maintained on my personal webpage (as PI), but I consider the group to be more than just "people who happen to be working with Prof. X".

In case it is helpful to have an example, here's mine: http://numerics.kaust.edu.sa/. I could give other examples of group sites I think are better than mine, but I don't know if they would like me advertising them as such.