@observer thanks for the question!!.
First of all imagine having a blog farm of your own and using pages to build post ("for clients") in order to have the article up to link out from there...
It will be a matter of time before Google ID that all the domains are part of a Blog Farm.. (and eventually penalize)
The ending result will be that all of your blog will eventually link from one to the next domain.. this will leave a foot print if the process repeatedly takes place order after order..
A link wheel as we all know is a no. set of web 2.0 properties interlinked in a "wheel" structure, all pointing to your money site, It is not wrong to use any combination of properties to build these profiles (squidoo, wiki's, etc..) And if randomly managed a blog.
But taking this to a service for clients (specially with the volume of orders daily manage) is not a good idea to offer our clients their profiles hosted on a blog farm.
The idea on creating these profiles is to increase their authority.
Most of our clients are monthly, so there is weekly updates taking place to their nodes, unique fresh content, as well blog comments built around the profiles and all of the things our service clearly describe. So with all this taking place these profiles increase their page rank over time and you gain the "juice" faster.
There is no a limit on how many links should point out from the web 2.0 profile.
I will strongly recommend to keep this as low as possible so the PR Boost is not compromised.
PR Boost:
The Page Rank Boost given by the Source URL.
This is calculated by the following formula:
(10^PR)/(# outbound links)
For Example, a PR3 back link with 2 outbound link, will give you
(10^3)/2=(10*10*10)/2=1000/2=500 boost.
Another thing to keep in mind is "related content".
You can have a few money sites pointing out from the profile, (make sure they are all under the same niche).
Let me know if this clarify the question.