Not really. Email addresses that belong to an "opt in" list have opted to receive emails from, say, the list-purchasing company -- not your company. Even if the opt-in process includes language like, "Opt in to receive information from us, or offers from other companies we think you might enjoy," the fact is the recipient doesn't recall having a prior relationship with you, specifically. This makes it highly likely for the recipients to mark you as "spam" when you arrive in their inboxes. Hey, if they don't recognize you or remember opting in to communications from you ... can you blame them?
Someone voluntarily gives you their email address either online or in person so you can send them emails. They may pick certain types of email content they wish to receive, like specifically requesting email alerts when new blog posts are published. Opt-in email addresses are the result of earning the interest and trust of your contacts because they think you have something valuable to say.
Then, let's say you write 30 blog posts a month. That means you'd get 60 leads in a month -- 2 from each blog post. Now keep doing that for a year. The work you did to blog that first month will continue to drive leads throughout the year. That means you're actually getting 4,680 opt-in contacts a month by the end of a 12-month period because of the compounding effects of blogging -- not just 720 opt-in contacts (60 leads*12 months).
Keep the subject line and pre-header short: The subject line is crucial. Keep it short so the reader knows exactly what the email topic is about. And the pre-header text (also known as snippet text), don’t let it go to waste by using “To view this email in your browser…”. Instead, summarize the email or include a call to action (i.e., Use “FREESHIP” to get free shipping).