You can contact me on several ways.
If you search for an freelancer, which could help you with your vtigerCRM, or you looking for special features, please contact me on firstname.lastname@example.org.
I will try to respond as quick as possible.
Also, you could write a comment into my vtigerCRM Blog, if you have a general question on my work or vtigercrm.
German speaking people could use my german vtigerCRM Blog.
If your question generally concern vtigercrm, you could also post into the official vtiger forum on forums.vtiger.com. There are lots of helping users.
Every feedback to my extensions is welcome!