out bound link not good for any site for page rank and serp. if you want your site live long with good serp then you need to control your site obl.
This is a topic of some fair debate, so let me put it to you this way. Thought leaders in a market give links. Take a look at the SEO space. SEOmoz, Search Engine Land, Search Engine Journal, SEO Chat ... all link out to other sites generously. All have top rankings and hordes of traffic. However, if you're just running some plain old ecommerce site and you don't care to give good information to your market, you just want them to buy your junk, then opportunist86 is correct, you need to control your links.
My opinion is that you should make sure that your site has a few outbound links. If all your links are inbound it won't look natural.
How many is too many? Again, take a look at almost any authority site and you'll see copious outbound linking. Jonah_fish is right ... at least some outbound links need to be present.
If you link out to 5000 low-quality automated content sites, that's not cool. If you link out to 50 relevant human resources, there's nothing wrong with that.
I personally never have worried about it. If it makes sense to have an outbound link because of your content, then do so. But don't artificially add OBLs just because someone told you to do that.
yes it will be effect on serps and may be it will be cause of lacking our website ranking from serps.