To all of you thanks for your posts. If I would summarise I think the following points are of interest:
1. O/L can certainly meet a need and can give very real emotions and experiences (read that such is the cases when performing in the "academy" as well)
2. O/L can sometimes be as good as it gets for people who simply cannot have a R/L relationship - and it seems that in many of those cases they are in fact happy that this opportunity exists. I have read that in several cases their partners know and approve of it - apparently recognizing that there simply is an urge.
3. O/L can lead to very real R/L, that being of course something only to dream about for most people
4. I missed this one, so I add it myself: it is a great way and relavite safe way to explore likes and dislikes!

More suggestions?
Take good care, keep on playing - but keep it safe!