We are delighted to welcome you to the Eleventh ACM International Conference on Web Search and Data Mining (WSDM 2018) held in Los Angeles, California, USA, on February 5-9, 2018. Now in its eleventh year, WSDM has become a top tier conference in Web-inspired research relating to search and data mining. As in previous years, we continued observing a growth in number of submissions. The conference this year, with 514 valid submissions, maintained the major boost that was observed last year in Cambridge UK (with 505 submissions as compared to 386 in year 2016 in San Francisco). Interestingly, we saw an increase in 10% in abstract submissions with a record breaking 757 abstracts (as compared to 687 in 2017) but only 68% of those ended up as valid submissions. This is partly due to a relatively high number of invalid submissions that did not adhere to our new double-blind review policy.

The 514 valid submissions originated from 41 countries, out of which 84 (as compared to 80 in 2017) were accepted for full paper publication in the proceedings, thus reaching an acceptance rate of 16.12% (as compared to 15.94% last year) and within the range of the last 11 years (with a min of 15.5% and a max of 22.3%.) Unfortunately, three papers were withdrawn/rejected after acceptance due to their violations of WSDM guidelines. The final 81 papers that will be published in the proceedings are from 23 countries, spanning four continents, making this a truly international forum. Oral presentation slots were allocated to all papers. Yet, in order to maintain the single track model that most attendees prefer, we followed the spotlight short presentation plus poster approach that was introduced in 2012. Out of the 81 accepted papers, 58 were assigned such a two-minute spotlight slot, while 23 were assigned a long twenty-minute talk slot. The type of slot was chosen by the Senior PC members and Program co-chairs, mostly based on whether the topic and the content of the paper were best suited for a large group presentation or for a more focused and interactive poster style of presentation.

The double-blind flavor we adopted this year allowed the authors to indicate the source of their data set, or deployment environment (so as not to refer to major commercial search engines as has often been done in the past). However, we observed that several authors failed to indicate their conflict of interest (COI) adequately and we will make sure to enforce COI guidelines (through both awareness campaigns and hopefully automated tools) more rigorously now that the double-blind review policy has been adopted.