The new expansion is Small World: A Spider's Web, and like other recent SW expansions it consists of a few new races and special powers that can be mixed with those of the base game or other previously released expansions. The new races in A Spider's Web are Ice Witches, Skags and Slingmen, while the new special powers are Copycat, Lava and Soul-Touch. Backers at the "Spiderines" level of Days of Wonder's Kickstarter project for the digital Small World 2 game were able to design their own race or mini-expansion that DoW would then print for their personal use — but the backing level mentioned that these creations might end up in a published version as well, and Andrew Capel, Alex and Bill Gurski, and Randy Pitchford are all "Spiderines" who are credited in A Spider's Web. Here's an explanation of the new races, followed by some of the tokens you'll find in this expansion:
Another part of that Small World 2 Kickstarter project involved the creation of three new races and special powers that would debut in the digital game and be released in a printed version for those backers who wanted a copy. That small expansion — Small World: Royal Bonus, which contains the three races Fauns, Igors and Shrubmen and the three special powers Aquatic, Behemoth and Fireball — will now be released in a retail version.
Both A Spider's Web and Royal Bonus will be released in English, French, German, Italian, Japanese, Polish and Spanish; will first appear at Spiel 2014 in October; and will reach stores in November 2014. A Spider's Web includes a plastic storage tray and retails for $15/€14, while Royal Bonus contains just the cardboard bits and retails for $12/€10.
Aside from those two items, Days of Wonder is also bringing Small World: Necromancer Island and Leaders of Small World back to print. These two items, both initially released as free promotional items in 2010 and 2009 respectively, were shortly available again in late 2013 as DoW had extras not needed for its Small World 2 Kickstarter project. These expansions will each retail for $6/€5 and be available in November 2014.
(Update, Sept. 9, 2014: BGG readers have noted that the components image for A Spider's Web includes a leader token, and DoW's Adrien Martinot has confirmed that this expansion includes leader tokens for the three new races, while Leaders of Small World is a new printing of the 2013 version that included leader tokens for all races through the Royal Bonus expansion. Both Leaders and Necromancer will be available at Spiel 2014.)