For almost every online service, it is fundamental to understand patterns, differences and trends revealed by age demographic analysis—for example, take the discovery of malicious activity, including identity theft, violation of community guidelines and fake profiles. In the particular case of platforms such as Facebook, Twitter and Yahoo! Answers, user demographics have impacts on their revenues and user experience; demographics assist in ensuring that the needs of each cohort are fulfilled via personalizing and contextualizing content. Despite the fact that technology has been made more accessible, thereby becoming evermore prevalent in both personal and professional lives alike, older people continue to trail Gen Z and Millennials in its adoption. This trailing brings about an under-representation that has a harmful influence on the demographic analysis and on supervised machine learning models. To that end, this paper pioneers attempts at examining this and other major challenges facing three distinct modalities when dealing with community question answering (cQA) platforms (i.e., texts, images and metadata). As for textual inputs, we propose an age-batched greedy curriculum learning (AGCL) approach to lessen the effects of their inherent class imbalances. When built on top of FastText shallow neural networks, AGCL achieved an increase of ca. 4% in macro-F1-score with respect to baseline systems (i.e., off-the-shelf deep neural networks). With regard to metadata, our experiments show that random forest classifiers significantly improve their performance when individuals close to generational borders are excluded (up to 20% more accuracy); and by experimenting with neural network-based visual classifiers, we discovered that images are the most challenging modality for age prediction. In fact, it is hard for a visual inspection to connect profile pictures with age cohorts, and there are considerable differences in their group distributions with respect to meta-data and textual inputs. All in all, we envisage that our findings will be highly relevant as guidelines for constructing assorted multimodal supervised models for automatic age recognition across cQA platforms.

Promoting engagement and participation is vital for online social networks such as community Question-Answering (cQA) sites. One way of increasing the contribution of their members is by connecting their content with the right target audience. To achieve this goal, demographic analysis is pivotal in deciphering the interest of each community fellow. Indeed, demographic factors such as gender are fundamental in reducing the gender disparity across distinct topics. This work assesses the classification rate of assorted state-of-the-art transformer-based models (e.g., BERT and FNET) on the task of gender identification across cQA fellows. For this purpose, it benefited from a massive text-oriented corpus encompassing 548,375 member profiles including their respective full-questions, answers and self-descriptions. This assisted in conducting large-scale experiments considering distinct combinations of encoders and sources. Contrary to our initial intuition, in average terms, self-descriptions were detrimental due to their sparseness. In effect, the best transformer models achieved an AUC of 0.92 by taking full-questions and answers into account (i.e., DeBERTa and MobileBERT). Our qualitative results reveal that fine-tuning on user-generated content is affected by pre-training on clean corpora, and that this adverse effect can be mitigated by correcting the case of words.

There are several reasons why gender recognition is vital for online social networks such as community Question Answering (cQA) platforms. One of them is progressing towards gender parity across topics as a means of keeping communities vibrant. More specifically, this demographic variable has shown to play a crucial role in devising better user engagement strategies. For instance, by kindling the interest of their members for topics dominated by the opposite gender. However, in most cQA websites, the gender field is neither mandatory nor verified when submitting and processing enrollment forms. And as might be expected, it is left blank most of the time, forcing cQA services to infer this demographic information from the activity of their users on their platforms such as prompted questions, answers, self-descriptions and profile images. There is only a handful of studies dissecting automatic gender recognition across cQA fellows, and as far as we know, this work is the first effort to delve into the contribution of their profile pictures to this task. Since these images are an unconstrained environment, their multifariousness poses a particularly difficult and interesting challenge. With this mind, we assessed the performance of three state-of-art image processing techniques, namely pre-trained neural network models. In a nutshell, our best configuration finished with an accuracy of 81.68% (Inception-ResNet-50), and its corresponding Grad-Cam maps unveil that one of its principal focus of attention is determining silhouettes edges. All in all, we envisage that our findings are going to play a fundamental part in the design of efficient multi-modal strategies.