Email is almost 40 times more effective than Facebook and Twitter combined in helping a business acquire new customers. (McKinsey, 2014)
Let it be Corporates, Brands, SME or Individuals; the effective way to send in more content is via Mails. On shared hosting there comes a restriction of no. of mails to be sent per day where the number floats around 200 to 500 max. If still you blast out more mails your shared hosting account your mail id is likely to get blacklisted and all your mails would land in spam.
The only best option left out is opt for bulk mailing services, however if you have 100% subscribed data then there are companies offering your services which assures you Inbox delivery and the probability of the mail id or domain blacklisting is negligible. But in most of the scenarios the data is either bought from some agencies (which is never 100% authentic) or is very old where again the data would not be 100% accurate.
In these scenario it is important to choose a company where there sending routes (IP’s) are not black listed and also the reputation of the IP’s. Sending from a blacklisted IP is likely to send all your mails in SPAM. Also while sending a mail it is important you follow the CAN-SPAM norms.