Spam is spam. Sending unasked emails to those who did not permit you to do so is, well, spammy. But time and time again, I am asked for comments as if specific reasons for negating that email is a permission-based medium.
That said, there is a way to address “reach out” when you don’t have permission or know exactly who you should be contacting.
It’s all about the approach. Regardless of how important the topic is to the sender, sending unrequested emails is still technically spam. The last thing you want is to have your event tainted by those who disagree with your approach. Or to have folks correlate your event with unsolicited emails.
How to Reach Out
With that said, if you are not “selling” anything in the email itself and it is more of an invitation, you can minimize a potentially harmful impression with the proper approach. What I would do is tailor each email to the person/organization you are emailing. It takes extra effort but also reflects a personal approach.
Include specific details about their org and what they do to show why you believe their attendance would be of interest to them. Make a point of explaining the benefit of their attendance would be for them — and the community.
Putting forth the extra effort shows you take great care not to be spammy. Emailing recipients who did not provide prior permission will be more open to stated benefits than a sales pitch.
Let them know that if they are interested, you would be pleased to send more information via either a PDF or by snail mail (USPS). Include your website URL so they know where they can check you out to get more information and register. A simple registration form is an excellent idea if you want to get a handle on how many will attend.
The Best Way?
Include an easy-to-find place on your website where folks can get on your mailing list for that kind of stuff. This then gives you the ability to build your list over time. New contacts will see that option and your description of the benefits and what to expect if they join your list.
You then have permission to email them about future events. However, keep in mind that just because email addresses are displayed on a website doesn’t give you tacit approval to send sales-pitchy mass emails about things you will commercially benefit from.
I wrote an article about Cold Calling via Websites that you might find helpful. Know that taking the time to personalize each email while emailing selective contacts will better your chances in leaving a positive impression for your brand.