Use them on tier2.

Yep , exclusive networks are the best. I prefer homepage links though, blog networks are usually extremely abused. They typically, not always, have spun content and posts about random subjects. Think hemorrhoid creams, payday loans, then a post about las vegas hotels. While you may need all three in Vegas, they still don't look natural.

I referred a fellow WF member to a network I use as a starting phase for all of my projects and he ripped them off and did a chargeback on months of work. Now I'm not keen on referring anyone anymore. One bad seeds gotta ruin it for everyone.

Stay away from general use service, you can build your or partner with a few IMers.

Avoid large well known networks like the plague. Any network that becomes well know is an easily destroyed target.

Build your own private network via guest posts, it works much, much better.

After penguin updates guest blog is best way to promote our business or services any things

I think the tier two level is good take your links to the next level.

Blog networks have been absolute poison for a long time now ( that is public blog networks). If you are building your own private network it is a lot safer. But it also requires technical knowledge, effort, time and money... because you can't leave a footprint for Google to find.