I received a call to my voicemail and they hung up. I assume this is one of those services that calls to see if it is a valid phone number and a time when you will answer the phone. They can then sell the information to telemarketers. Just guessing....
If you're receiving calls from this number (TradePub), you most likely filled out a form on the internet somewhere. TradePub provides (usually free) subscriptions to I.T. trade journals, which explains why many of the other commenters indicate they received calls at their work number. They do offer some useful publications if you're into the I.T. scene, but they are just a tad aggressive. If you want the calls to stop, call the toll-free number that other commenters have listed and you should be able to have them remove your number from their dialer. I agree about having to deal with unwanted consumption of cell phone minutes - not everyone has an "unlimited" plan, so calls like these can start to get expensive if you receive a lot of them (especially since you're basically charged double for calls that go to voicemail - once for the minutes consumed when the call is recorded, and then again when you access your mailbox to retrieve the message). There really should be a law prohibiting that practice, but politicians obviously have other fish to fry that they deem more important than this...
Received call from this number as "Netline Corporation" on caller ID on a Monday at 14:25
No voice mail left,
Company identified as Marketing company on web