I'm trying plaxo, an adsense-supported PIM with FaceBook-like "connections".

The PIM offers the usual contacts, calendar, tasks, and notes - the exact same services on my ten-year old Palm. But Plaxo's versions are anemic (e.g., tasks lack a context, critical for GTD) and Plaxo is awkward (everything requires multiple clicks; most operations seem much faster at google). Plaxo's saving grace is synchronization with its competitors (google and yahoo calendar and address book) and with desktop programs (Outlook and the Mac retinue). Plaxo doesn't actually sync with your Palm or cell phone, but there is a lite version of the web site, barely usable on networked PDAs and phones (m.plaxo.com). Unfortunately it's still baking: Plaxo doesn't seem to display all the entries on my google calendar.

Plaxo's "connections", a subset of your contacts, are links to other Plaxo members. When those members change their contact information, your address book automatically reflects the update. This sounds like a great feature, but it works only for your friends using plaxo. Plaxo also shows your contact's favorite RSS feeds, which again sounds great - a single list of everyone's activities and photos - but again, it shows information only from those who've already signed up for plaxo, and shows only the first few words of each blog entry - it can't compete with a proper feed reader.

I'm not sure what, if anything, I'll use plaxo for. I already store my calendar and addresses on google's services, and see no reason to switch to plaxo. I could use plaxo as a backup, in case google ever goes down; plaxo could also backup my google data to a PC, in case I ever need to work disconnected from the net. I suppose if enough if my contacts eventually join plaxo, I might use it as a social network, competing with facebook. I'm not holding my breath.