Improving first impressions on Signal

The phenomenon of unsolicited and unwanted messaging dates back to the earliest communication platforms: from prehistoric cave graffiti and postal chain letters to popup ads and robocalls. To prevent spam, most online services rely on large-scale inspection of plaintext conversation content or detailed social-graph analysis to determine who is saying what to whom and whether or not that should be allowed. At Signal, we build on a foundation of privacy and do not have access to that type of data or metadata.