When a company has a buyback, it means that the company is going out and buying shares of its own company on the open market. This is generally very bullish for stocks, since it shows confidence by executives in their own companies, reduces the number of shares outstanding - making them scarcer [scarcity causes price increases], and it means that the earnings and dividends are split up among fewer shares, benefiting the remaining shareholders.
An article in TheStreet.com lists all the buybacks that were announced for the last month and a half. Here are the announcements from yesterday [January 24]:
Disclosure: Author owns EBAY.