For the most popular professionals, the invites just keep coming.

One of the fastest-growing popular web communities for businesspeople is the networking site LinkedIn. Many of us are linked to LinkedIn, and many of us wonder why.

Why would your toga-wearing college buddy who now runs a lucrative reinsurance business in New Jersey want to be electronically tied to your former boss who's painting watercolors in Napa Valley? (Come to think of it, you never liked either one of them very much, so maybe it's a perfect match.)

Some of us receive frequent e-mails saying that someone we know -- or might know or forgot we knew -- wants to add us as a "connection'' to their LinkedIn network. What's the etiquette for that? How can you say no? And what are we actually committing to, besides more e-mail?

You worry that if you say no to a LinkedIn invite the world will pass by, leaving you looking like the 11th guy picked for the basketball game. If you're not linked, you stink. What if everyone else in the office discovers you're no longer accepting LinkedIn invites? Imagine the hazing.

The initial lure of LinkedIn is that for most of us it's a complete waste of time, but it looks and feels like work. You can get in trouble for spending too much work time at, but any boss on the cutting edge will understand why you need to update your profile at LinkedIn. Where else can you have an intelligent e-mail discussion on leadership?

You can also turn to LinkedIn for advice on doing business in Tierra del Fuego. Ask your new virtual associates what to do about a botched vasectomy, severe hangovers or work-induced narcolepsy.

Or you can ask for advice on dealing with low performers in the workplace. Just don't name names: There's always a chance your human resources director is linked in, too.