Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of mobile multimedia maven BroadSoft (Nasdaq: BSFT) fell as much as 13.1% on fairly average trading volume.

So what: As of last night's closing, BroadSoft shares has gained more than 500% since its IPO in June. IPO underwriters are coming off their lock-up period and will be able to sell their shares and options this Friday, and now seems like an opportune time to lock in some profit before that pricing pressure arrives.

Now what: Small caps whose IPO papers still smell of fresh ink are tricky investments at best. A cheerful analyst note can send the stock soaring one day, only to come back to earth on no news at all the next. That's exactly what just happened to BroadSoft. Fellow voice-over-IP specialist Vonage Holdings (NYSE: VG) took the opposite path four years ago, and it's still prone to wild and mysterious mood swings.

Interested in more info on BroadSoft? Add it to your watchlist.

Fool contributor Anders Bylund holds no position in any of the companies discussed here. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool is investors writing for investors.