Twitter recently announced a number of significant rule and policy changes designed to counteract some common uses and abuses of the Twitter system.
Hashtag spam - The aggressive use of hashtags to inflate the prominence of certain tweets - is among the targets of Twitters new policies. Twitter has indicated they will aggressively enforce rules that prohibit hashtag spam. Enforcement action may include suspension or termination of Twitter accounts that violate Twitter's rules.
To protect our users from violating Twitter's policies, dlvr.it will no longer automatically append #hashtags as prefixes, suffixes on Tweets.
For more details, please read our blog post on the updated Twitter rules.