I have a community of 7,000 users, but have not implemented a newsletter yet. Any advice on which service I should use and how I should introduce it to my community?
There are a ton of email service providers out there. For that size of a list, you will probably be spending at least a little bit of money. My favorite ESP is CampaignMonitor - http://campaignmonitor.com - but a lot of people really like MailChimp, Emma, or CakeMail.
I would recommend doing two things to announce it - (1) Add something on the community site. If you have a sidebar or area on the front and other pages - add a section with a quick blurb on what it is along with a signup form. (2) If you have the community users' emails, send them an email with an invitation to sign up for the newsletter. Since they already signed up for the community - this would fall under the umbrella of transactional email - so you don't technically need permission from them to send them email - I just wouldn't use this list for the actual newsletter list - just to ask their permission to get on the newsletter list.
If users have a dashboard page or something similar, you can always make an announcement there as well. The main thing is that you want them to give you express permission to start sending them newsletters. Don't just start blasting to that list.
I would recommend doing two things to announce it - (1) Add something on the community site. If you have a sidebar or area on the front and other pages - add a section with a quick blurb on what it is along with a signup form. (2) If you have the community users' emails, send them an email with an invitation to sign up for the newsletter. Since they already signed up for the community - this would fall under the umbrella of transactional email - so you don't technically need permission from them to send them email - I just wouldn't use this list for the actual newsletter list - just to ask their permission to get on the newsletter list.
If users have a dashboard page or something similar, you can always make an announcement there as well. The main thing is that you want them to give you express permission to start sending them newsletters. Don't just start blasting to that list.