This is a section of my Hub on 1099's. Hope it helps.
1099K Merchant Card and Third-Party Network Payments
Banks and other payment settlement entities, such as PayPal, are required to report payment card and third-party network transactions with their participating merchants. 2011 was the first year this form was required to be used.
Unlike a 1099-MISC, the 1099-K is for informational purposes. Basically, it documents the credit card or third party network payments you receive in return for goods or services. Most likely, you will already have records documenting these transactions when they occurred. Do not double count the transaction records (gross receipts) and the 1099-K.
With the 1099-K, the IRS hopes to decrease underreporting of these types of transactions and thus underreporting of income and the subsequent income tax owed by small business owners.
If you received $600 or more as a single or aggregate payment from a third-party network or credit card company, you will receive a 1099-K by January 31st. This will affect a lot of people who run eBay or other on-line businesses. Since writers on HubPages are paid only through PayPal, a third party network, writers will no longer receive a 1099-MISC from HubPages, but will instead receive a 1099-K from PayPal.