To expand on what LOTR said.

Limewire does not tell you if anyone has the whole torrent i.e. seeds vs. peers
Limewire has no way of adding torrents just for sharing
Limewire doesn't have the ability to make a torrent
Limewire has a very un-userfriendly way of sharing torrents back. Pretty much it renames stuff it shouldn't be renaming. In a real torrent client you can have as many torrents loaded as you want. This way you can share back even if the initial swarm did not need you to.

Many trackers ban Limewire/Frostwire and the likes. Reasons:

Not a real bittorrent client
Sends bad data to tracker
Does not update properly
etc. etc.

If the developers would have contacted and worked with other devs/staff when developing Bittorrent support in the client, then it wouldn't be like this.

The "Service" you are speaking of is Limewire users draining BitTorrent swarms, taking what it wants and not giving back. Using it for torrents makes you anti P2P-sharing.