eBay, the online auction giant, is doing a bit of Spring cleaning.

On Monday, it announced that it had sold StumbleUpon, a content discovery service it purchased for $75m in May 2007, back to its founders and a group of venture capitalists.

And then yesterday, following rumors that it was looking at selling online VoIP leader Skype back to its founders, eBay announced that it was spinning Skype off and would be taking the company public in 2010. eBay acquired Skype for a rich $2.6bn in 2005 and was forced to write off nearly $1bn of that amount.

Why the moves by eBay? Put simply, unlike PayPal, which eBay acquired in 2002, neither StumbleUpon or Skype was a good fit with eBay’s core business.

Many looked at StumbleUpon as a bizarre acquisition for eBay when the deal was first announced and under eBay’s umbrella, StumbleUpon basically stagnated. No synergies were ever realized between the companies. Skype is a successful business, with over 400m registered users and $551m in revenues in 2008. It looks poised to continue its impressive growth; eBay’s projections have Skype earning $1bn in 2011. But it too offered few synergies.

eBay’s president and CEO, John Donahoe, described the Skype spin-off and IPO in honest terms:

Skype is a great stand-alone business with strong fundamentals and accelerating momentum. But it’s clear that Skype has limited synergies with eBay and PayPal. We believe operating Skype as a stand-alone publicly traded company is the best path for maximizing its potential.

He explained that the Skype divestment will enable eBay to focus on its core businesses: ecommerce and payments. Some investors seemed to approve of that message, sending eBay’s stock up in afterhours trading.

Obviously this is good news for eBay and for StumbleUpon and Skype. eBay gets back to basics and StumbleUpon and Skype get new life as independent companies. That’s probably the way it should have been in the first place.

So is this the beginning of a trend? PaidContent’s Rory Maher suggests some other ‘ill-considered acquisitions that could lead to sales, including Bebo, which was the subject of such rumors in the past.

I personally believe there’s another possible trend to watch for: fewer acquisitions overall going forward. Boom and bust cycles are not new to the business world but this last one has been especially painful on so many levels. A lot of people suggest that the world has changed and that things won’t be the same again anytime soon. I think there just might be something to this and there’s a good chance companies will be far more conservative going forward when it comes to M&A activity, even when the global economy rebounds. After all, so many companies have been burned by big acquisitions and that’s not something easily forgotten.

Obviously fewer big acquisitions would be bad news for many startups and their investors. But it’s also good news since a more realistic market for M&A could give startups a greater incentive to build the next big standalone companies of tomorrow.

Photo credit: Dru Bloomfield via Flickr.