Cable Forum often considers links to commercial websites as spam. Post in the majority of areas of this board, including as links in signatures or profiles, and the Team might well get upset, unless it is something very on topic and the poster isn't joining in a thread simply promote their services as part of an on topic answer.
This thread, and this thread only, is slightly more relaxed. A single link to a commercial site may be acceptable, provided that this is not a repetitive process. If someone is linking to a site that is simply making money from loads of adverts and other page visits it's unlikely to be acceptable. Forum users who are long standing and active are likely to get a much greater level of latitude than someone who has only been here a few days. Of course if you've been told before your link is unacceptable, for some reason, it's not going to be permissible here.
Ultimately it will be a judgement call from the Team if we see something we don't like, but we don't go looking for trouble, believe it or not
Realistically this thread is here to primarily allow members' leisure and hobby sites to receive a little exposure, rather than for commercial purposes.