CREATE TABLE torrents (groupname TEXT, totalsnatched DECIMAL, artist TEXT, groupyear DECIMAL, releasetype TEXT, groupid DECIMAL, id DECIMAL)
CREATE TABLE tags (index DECIMAL, id DECIMAL, tag TEXT)

What type of musical album is the most popular?
SELECT T1.tag FROM torrents AS T2 JOIN tags AS T1 ON T1.id = T2.id WHERE T2.releasetype = "album" GROUP BY T1.tag ORDER BY SUM(T2.totalsnatched) DESC LIMIT 1
SELECT "T1"."tag" FROM "torrents" AS "T2" JOIN "tags" AS "T1" ON "T1"."id" = "T2"."id" WHERE "T2"."releasetype" = "album" GROUP BY "T1"."tag" ORDER BY SUM("T2"."totalsnatched") DESC NULLS LAST LIMIT 1