In order to contact i_heart_dogs, you need to become a paid member.
There are two types of paid membership.
Unlimited Pass -- An unlimited pass is good for 7 days, 30 days or 90 days, and entitles you to email as many members as you like during that period. Most people prefer a paid pass because there is no limit to the number of members you can contact.
Stamps -- Stamps are the "pay-as-you-go" option. Stamps never expire, and it takes 2 stamps to email another memnber. Once you have contacted a particular member, no more stamps are required to continue corresponding back and forth with the same member.) Stamps are sold in books of ten, enough stamps to initiate five emails.