What are some alternatives?
When comparing Site Search 360 and Constant Contact, you can also consider the following products
Algolia - Algolia's Search API makes it easy to deliver a great search experience in your apps & websites. Algolia Search provides hosted full-text, numerical, faceted and geolocalized search.
MailChimp - MailChimp is the best way to design, send, and share email newsletters.
Swiftype - The simplest way to add search to your website or application. Sign up for free.
SendInBlue - Innovative online Email Marketing solution to manage your contacts, create & send your newsletters and track your results. More than 80 000 clients. Best prices and attractive features.
ElasticSearch - Elasticsearch is an open source, distributed, RESTful search engine.
HubSpot - HubSpot is an inbound marketing and sales platform that helps companies attract visitors, convert leads, and close customers.