OOB searching is intended to help with finding the rarer files, however has proved in the most recent LW versions (since LW 4.12) to cause some issues.

Being an ultrapeer helps with the network. People need to connect to ultrapeers to connect to the gnutella network (LW Basic users connect to 3, Pro users to 5.) Ultrapeers also take in much of the search traffic & shields the leafs from unnecessary information. Being an ultrapeer can however affect uploading abilities to a certain extent. The network decides who becomes an ultrapeer when needed if their abilities are capable & they have the option enabled.

DHT & TLS have been introduced in recent versions of LW. There have been known bugs with them. I have no idea whether all have been fixed since LW has not issued an updated history changes in their version updates for a while.

It's nice seeing people upload at a nice rate. Having too many upload slots (depending on your upload bandwidth capabilities) can mean many lose out with slow upload speeds, or one gets most whilst the others suffer.

Uploading helps with downloads. Uploading means you are connected indirectly with more people of the network & helps with searches. You can also sometimes browse uploaders.

I use ADSL2 which means my upload bandwidth does not affect my download bandwidth. However those who use DSL may have their total bandwidth btw upld & downld shared, thus the faster one downloads, the slower uploads are, or vice versa. So that can affect how you decide upon upload slots & speed. (Dial up is a typical example of what I mean by shared bandwidth between upload & download.)

Some more tips in the stickies in this section in regards to using LW.