It's impossible to say exactly why shares of Adobe Systems (NASDAQ:ADBE) sold off 2% today. Some investors may have sold because the company forecasted a smaller margin for the next quarter, some may have hoped for even better numbers, some perhaps thought it was a good time to lock in a profit, and some may have had concerns that turmoil over at Red Hat (NASDAQ:RHAT) may be related to Internet fundamentals. Macromedia (NASDAQ:MACR) and Novell (NASDAQ:NOVL) also traded lower today.

The thing these four companies have in common is that they all provide products used to create or display websites. In Novell's case, that is only slightly true given that it only recently purchased SUSE LINUX and doesn't yet rely heavily on the product for revenue. But given that Red Hat -- its closest competitor in the Linux software market -- dropped more than 10% today, it's understandable that Novell would follow suit.

However, there really wasn't much of a reason for selling Adobe Systems today. The second-quarter results certainly didn't give investors a reason to want to sell. Nor did they provide any information that should seriously concern investors about its future.

Revenue increased 28% to $410.1 million in the second quarter of fiscal 2004 thanks to record sales of its Creative Suite and Acrobat products. Yes, it's less than the $423.3 million in sales during the first quarter, but the company's business is cyclical, the lower results were expected, and the company did better than its lower expectation. Net income increased to $109.4 million from $64.2 million a year earlier, but also was down from the first quarter.

As for its outlook, it is expecting its operating margin to drop to a range 28% to 31% for the third quarter from nearly 35%. But the company explains that the reduction in expected margin is due to annual raises that will come during the quarter and investing in R&D, including the addition of 130 employees. In my view, the hiring and investment in R&D shows the optimism it has for the market for its products.

Motley Fool contributor Mark Mahorney doesn't own shares of any companies mentioned.