Cross website promotion
 

Hey site owners,

I suggest we can promote each others' sites for mutual benefits. Perhaps I can bring some of my viewers to your sites and you can bring me some of yours by including promotional contents and links. Should we do this? Please let me know what you think! You can pm me if you are interested!

That would be effective; however, your site's main topic may not be relevant to our sites so we need to determine whether your site's main topic is relevant to ours or not.

Cross website promotion was relevant a few years ago but can get you penalised now. Better not to do it.