I'm not sure which site you're referring to. There are no rules here against cross-posting on other sites. You may not cross-post on other forums in CoffeeGeek. See below:
No cross posting allowed - do not post your topic to more than one forum, nor repost a topic to the same forum.
From the FAQ:
Q What is cross posting? A Cross posting is the act of posting the same topic across several forums categories or several posts within the same product category. People usually do this to try and garner more responses to their questions or to advertise a product or service to more people. Cross posting is not allowed on CoffeeGeek forums.
Q Why is cross posting not allowed? A Cross posting is not allowed in CoffeeGeek forums for a variety of reasons, including: it "pollutes and dilutes" the forum topic listings pages; it adds unnecessary bulk to our forums, slowing down our server and database software; it often used by businesses and individuals, including stealth advertisers, to get the word out about their product; and it allows for an environment where some topics become overbearing. Cross posting is strictly not allowed on CoffeeGeek, and will be administered by our forum Moderators.
I think Home-Barista does not like posts from CoffeeGeek posted over there, and there is enough overlap in the readership to make it superfluous, but there is no specific CoffeeGeek rule prohibiting it.
Dana Leighton - Espresso hack and CoffeeGeek moderator
Symbols: = New Posts since your last visit = No New Posts since last visit = Newest post
Forum Rules: No profanity, illegal acts or personal attacks will be tolerated in these discussion boards. No commercial posting of any nature will be tolerated; only private sales by private individuals, in the "Buy and Sell" forum. No cross posting allowed - do not post your topic to more than one forum, nor repost a topic to the same forum. Who Can Read The Forum? Anyone can read posts in these discussion boards. Who Can Post New Topics? Any registered CoffeeGeek member can post new topics. Who Can Post Replies? Any registered CoffeeGeek member can post replies. Can Photos be posted? Anyone can post photos in their new topics or replies. Who can change or delete posts? Any CoffeeGeek member can edit their own posts. Only moderators can delete posts. Probationary Period: If you are a new signup for CoffeeGeek, you cannot promote, endorse, criticise or otherwise post an unsolicited endorsement for any company, product or service in your first five postings.