Carto, or Carto Builder, is a web-based drag and drop tool for mapping, sharing, and analyzing location data within a browser.
Free version is available, but your data will be publicly available in the cloud.
Can upload many common geospatial formats or tabular data with locational attributes: Shapefile, KML, KMZ, GeoJSON, CSV, Excel, Open Document Spreadsheet, GPX, OSM, and MapInfo.
Lots of options for import/export, styling, connecting with data dynamically, and analysis..
Build your own mapping portal and publish it to the world or to just a few collaborators. WorldMap is open source software.
WorldMap is being developed by the Center for Geographic Analysis at Harvard University, based on open source GeoNode software.
Strong focus on the ability to upload and download larger geographic layers. Upload shapefile and geoTIFF formats. Download in such formats such as KML, shapefile, spreadsheet, and PDF.
Create and edit maps and link map features to media content, Collaborate and share output, if desired. See the Summary of features.
Georeference scanned images of paper maps online in WorldMap using Harvard's WorldMap Warp. See this guide's page on cloud-based georeferencing apps.
Basic edition is free and allows uploading up to 100 geographic features per map, up to 5 maps.
Can upload data from Google Spreadsheets, Excel, CSV, KML, and GeoRSS feeds.
Carto.com
